The present disclosure relates to an imaging apparatus and a method of calculating a usable time of an imaging apparatus.
In recent years, portable electronic devices such as digital video cameras have increased in number, and the performance of secondary batteries mounted in such electronic devices has become important. As one of such secondary batteries, there is a battery called a lithium-ion battery.
In addition, many portable electronic devices which use a secondary battery as a power supply as described above have a function of displaying a remaining battery level. In particular, the lithium-ion secondary battery has properties of gradually and linearly reducing a battery cell voltage excluding immediately after the start and immediately before the end of discharge, so that the remaining battery level can be relatively accurately predicted and displayed.
In addition, in order to predict the battery capacity more accurately, battery packs made by accommodating detection circuits of a battery cell voltage or current, a microcontroller which performs various correction processes as described above, and the like in the same packages as battery cells have been made commercially available. Such a battery pack communicates with a device as a discharge load and has a function of outputting various internal detection values to the device, thereby enabling the device that receives the detection values to calculate and display a remaining battery level or a usable time (for example, refer to Japanese Unexamined Patent Application Publications Nos. 2009-44895 and 2003-240830.